Vulnerability-Lookup

FKIE_CVE-2026-4438

Vulnerability from fkie_nvd - Published: 2026-03-20 20:16 - Updated: 2026-03-23 15:16

Severity ?

5.4 (Medium) - CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N

Summary

Calling gethostbyaddr or gethostbyaddr_r with a configured nsswitch.conf that specifies the library's DNS backend in the GNU C library version 2.34 to version 2.43 could result in an invalid DNS hostname being returned to the caller in violation of the DNS specification.

References

	URL	Tags
	3ff69d7a-14f2-4f67-a097-88dee7810d18	https://sourceware.org/bugzilla/show_bug.cgi?id=34015

Impacted products

	Vendor	Product	Version

JSON

To clipboard

{
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "Calling gethostbyaddr or gethostbyaddr_r with a configured nsswitch.conf that specifies the library\u0027s DNS backend in the GNU C library version 2.34 to version 2.43 could result in an invalid DNS hostname being returned to the caller in violation of the DNS specification."
    }
  ],
  "id": "CVE-2026-4438",
  "lastModified": "2026-03-23T15:16:35.680",
  "metrics": {
    "cvssMetricV31": [
      {
        "cvssData": {
          "attackComplexity": "LOW",
          "attackVector": "ADJACENT_NETWORK",
          "availabilityImpact": "NONE",
          "baseScore": 5.4,
          "baseSeverity": "MEDIUM",
          "confidentialityImpact": "LOW",
          "integrityImpact": "LOW",
          "privilegesRequired": "NONE",
          "scope": "UNCHANGED",
          "userInteraction": "NONE",
          "vectorString": "CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N",
          "version": "3.1"
        },
        "exploitabilityScore": 2.8,
        "impactScore": 2.5,
        "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
        "type": "Secondary"
      }
    ]
  },
  "published": "2026-03-20T20:16:49.623",
  "references": [
    {
      "source": "3ff69d7a-14f2-4f67-a097-88dee7810d18",
      "url": "https://sourceware.org/bugzilla/show_bug.cgi?id=34015"
    }
  ],
  "sourceIdentifier": "3ff69d7a-14f2-4f67-a097-88dee7810d18",
  "vulnStatus": "Awaiting Analysis",
  "weaknesses": [
    {
      "description": [
        {
          "lang": "en",
          "value": "CWE-20"
        }
      ],
      "source": "3ff69d7a-14f2-4f67-a097-88dee7810d18",
      "type": "Secondary"
    },
    {
      "description": [
        {
          "lang": "en",
          "value": "CWE-88"
        }
      ],
      "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
      "type": "Secondary"
    }
  ]
}

CVE-2026-4438 (GCVE-0-2026-4438)

Vulnerability from cvelistv5 – Published: 2026-03-20 19:59 – Updated: 2026-03-23 15:06

Title

gethostbyaddr and gethostbyaddr_r return invalid DNS hostnames

Summary

Severity ?

5.4 (Medium)


                        
                          CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N

CWE

CWE-20 - Improper input validation

Assigner

glibc

References

URL

Tags

https://sourceware.org/bugzilla/show_bug.cgi?id=34015

Impacted products

	Vendor	Product	Version
	The GNU C Library	glibc	Affected: 2.34 , ≤ 2.43 (custom)

Date Public ?

2026-03-20 22:17

Credits

Antonio Maini (0rbitingZer0) - 0rbitingZer0@proton.me

Show details on NVD website

JSON

To clipboard

{
  "containers": {
    "adp": [
      {
        "metrics": [
          {
            "cvssV3_1": {
              "attackComplexity": "LOW",
              "attackVector": "ADJACENT_NETWORK",
              "availabilityImpact": "NONE",
              "baseScore": 5.4,
              "baseSeverity": "MEDIUM",
              "confidentialityImpact": "LOW",
              "integrityImpact": "LOW",
              "privilegesRequired": "NONE",
              "scope": "UNCHANGED",
              "userInteraction": "NONE",
              "vectorString": "CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N",
              "version": "3.1"
            }
          },
          {
            "other": {
              "content": {
                "id": "CVE-2026-4438",
                "options": [
                  {
                    "Exploitation": "none"
                  },
                  {
                    "Automatable": "no"
                  },
                  {
                    "Technical Impact": "partial"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2026-03-23T15:06:13.636418Z",
                "version": "2.0.3"
              },
              "type": "ssvc"
            }
          }
        ],
        "problemTypes": [
          {
            "descriptions": [
              {
                "cweId": "CWE-88",
                "description": "CWE-88 Improper Neutralization of Argument Delimiters in a Command (\u0027Argument Injection\u0027)",
                "lang": "en",
                "type": "CWE"
              }
            ]
          }
        ],
        "providerMetadata": {
          "dateUpdated": "2026-03-23T15:06:16.376Z",
          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP"
        },
        "title": "CISA ADP Vulnrichment"
      }
    ],
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "glibc",
          "vendor": "The GNU C Library",
          "versions": [
            {
              "lessThanOrEqual": "2.43",
              "status": "affected",
              "version": "2.34",
              "versionType": "custom"
            }
          ]
        }
      ],
      "credits": [
        {
          "lang": "en",
          "type": "finder",
          "value": "Antonio Maini (0rbitingZer0) - 0rbitingZer0@proton.me"
        }
      ],
      "datePublic": "2026-03-20T22:17:00.000Z",
      "descriptions": [
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              "type": "text/html",
              "value": "\u003cdiv\u003eCalling gethostbyaddr or gethostbyaddr_r with a configured nsswitch.conf that specifies the library\u0027s DNS backend in the GNU C library version 2.34 to version 2.43 could result in an invalid DNS hostname being returned to the caller in violation of the DNS specification.\u003c/div\u003e"
            }
          ],
          "value": "Calling gethostbyaddr or gethostbyaddr_r with a configured nsswitch.conf that specifies the library\u0027s DNS backend in the GNU C library version 2.34 to version 2.43 could result in an invalid DNS hostname being returned to the caller in violation of the DNS specification."
        }
      ],
      "impacts": [
        {
          "capecId": "CAPEC-142",
          "descriptions": [
            {
              "lang": "en",
              "value": "CAPEC-142 DNS Cache Poisoning"
            }
          ]
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "cweId": "CWE-20",
              "description": "CWE-20 Improper input validation",
              "lang": "en",
              "type": "CWE"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-03-20T19:59:06.064Z",
        "orgId": "3ff69d7a-14f2-4f67-a097-88dee7810d18",
        "shortName": "glibc"
      },
      "references": [
        {
          "url": "https://sourceware.org/bugzilla/show_bug.cgi?id=34015"
        }
      ],
      "source": {
        "discovery": "UNKNOWN"
      },
      "title": "gethostbyaddr and gethostbyaddr_r return invalid DNS hostnames",
      "x_generator": {
        "engine": "Vulnogram 1.0.1"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "3ff69d7a-14f2-4f67-a097-88dee7810d18",
    "assignerShortName": "glibc",
    "cveId": "CVE-2026-4438",
    "datePublished": "2026-03-20T19:59:06.064Z",
    "dateReserved": "2026-03-19T19:55:44.639Z",
    "dateUpdated": "2026-03-23T15:06:16.376Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}

Sightings

Author	Source	Type	Date

Nomenclature

Seen: The vulnerability was mentioned, discussed, or observed by the user.
Confirmed: The vulnerability has been validated from an analyst's perspective.
Published Proof of Concept: A public proof of concept is available for this vulnerability.
Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
Not confirmed: The user expressed doubt about the validity of the vulnerability.
Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.

Detection rules are retrieved from Rulezet.

Action not permitted

FKIE_CVE-2026-4438

CVE-2026-4438 (GCVE-0-2026-4438)

Tags

Sightings

Nomenclature